The present application relates to processing of data streams and more particularly to techniques for detecting recurring non-occurrences of an event over multiple time periods.
Databases have traditionally been used in applications that require storage of data and querying capability on the stored data. Existing databases are thus best equipped to run queries over finite stored data sets. However, the traditional database model is not well suited for a growing number of modern applications in which data is received as a stream of data events instead of a bounded data set. A data stream, also referred to as an event stream, is characterized by a real-time, potentially continuous, sequence of events. A data or event stream thus represents unbounded sets of data. Examples of sources that generate data streams include sensors and probes (e.g., RFID sensors, temperature sensors, etc.) configured to send a sequence of sensor readings, financial tickers, network monitoring and traffic management applications sending network status updates, click stream analysis tools, and others.
Pattern matching is commonly used for analyzing data. For example, data stored in a database may be analyzed to determine if the data matches a pattern. It is desirable to efficiently perform pattern matching on data received in the form of data or event streams.